Biochar - an answer to late-season weeding

This year, my compost pile grew exponentially, as did my composting skill. Do you know what else grew exponentially this year? Volunteer tomatoes, in every one of my garden beds and containers! Why? Because last year's compost pile never got hot enough to sterilize the plethora of rotten tomatoes that went into it as I cleaned up last year's depleted garden beds.

Look at all those baby tomatoes...

This year, aside from tomatoes that I'll have to compost, I also have a ton of weeds that I allowed to go to seed. My squash went wild into my grass, which prevented me from mowing everywhere I wanted. It did not prevent me from using the string trimmer, that was just my general inattentiveness! Regardless, I have massive amounts of unwanted cultivars seeding in my garden that I do not want to risk putting into my compost. It is getting colder out and I can't guarantee a sterilizing amount of heat anymore this year. So what options do I have? 

Two options are to just toss all those seeding plants into a brush pile or yard waste container. Either way,  you miss out on all the benefits of organic fertilizer. Notice I didn't say compost, because there are many other options for turning your unwanted organic materials into a useful soil amendment!

When is a tomato a weed?
When it grows in your kale.

Before I get into the main topic,  I want to briefly touch on a few of the other options we have when it comes to utilizing yard and kitchen waste.

Hot composting: this can either be open-air compost piles or in a compost tumbler. Both are above-ground options that utilize bacteria and organisms to break down organic materials into nutrient-rich soil. 

Direct composting: this form of composting takes place in the existing soil. You can bury or till your plants right where they grew to return those much-needed nutrients back to the ground where they came from. You could also consider Core Gardening as a form of direct composting. 

Vermicomposting: this is composting with a twist. A creepy-crawly, wiggly twist. You build a home for worms and allow them to turn your stinky food scraps into that sweet, sweet (please don't eat it) 'Black Gold' worm castings. A very rich soil additive!

Compost tea: it is what it sounds like; tea made from steeping compost in water. The organic matter goes into a bucket of water and rots. The water is used to fertilize plants. It stinks. Do this away from the house and patio.

Some of these radishes look bizarre...

And now on to our main event: biochar!

I will admit, this is the first year I've made biochar on purpose. I had a problem with seeding weeds everywhere,  and this seemed like a multi-tiered solution. 

Biochar uses essentially the same process as making charcoal, but rather than creating a cooking fuel, you are using your weeds and spent veggies, along with some hardwood, to make a carbon-rich soil amendment. 

Biochar is organic material that is burnt slowly at a (relatively) cool temperature in a low oxygen environment. To better know what it is, it seems appropriate to discuss how it's made. 

- A simple setup is to dig a pit a few feet across and about 1 and a half feet deep. Reserve the soil close by. 

- Build a good hardwood fire in the pit. It doesn't have to be big; this is gardening, not a bonfire! 

*Make sure the wood you use is cured, dry hardwood for a good hot base fire. Don't use construction cause these often contain harmful chemicals and metal hardware that is unwanted in the garden, and is usually softwoods that burn away too quickly.

- When the topmost logs begin to turn white along the top edges of the wood, start stacking your green cuttings on top. This will smoke a lot, so please check all local rules before burning! 

- Ensure the fire is still going as you cover it with the garden scraps. This has to stay hot for the next step.

-Once everything is piled on, take that soil you dug out of the hole and bury it all. The dirt will choke out all the oxygen, but the coals will continue to stay hot for many hours!

-Come back the next day and dig it all up. You now have a pile of biochar!

Sorry little tomato plants,
you are destined to be fertilizer!

This process is called Pyrolysis, in which the slow and cool nature of the burn turns the carbon into a solid state that is stable and won't decompose. When plants grow, they pull carbon from the air (CO2). They release oxygen and use the carbon as building materials so they can grow. When that plant rots the carbon is re-released into the air. During pyrolysis,  we can trap that carbon and use it to our benefit. 

Biochar can be added to garden beds in a mix of 1 part biochar, one part compost, 2 parts soil. The biochar has the great ability to absorb water and slowly redistribute it to plant roots. This will help keep your garden green in the hot summer. 

It also helps prevent soil compaction and therefore is wonderful in hard clay soils.

It will also slowly feed your plant roots the carbon and will last much longer than compost.

But the main benefit for me, the whole reason we're here today? When you burn weed seeds, they can't germinate! Take that, tomatoes! You aren't volunteering in this garden anymore!🔥🍅🔥